What's your question? Ask

We did not receive your images.
Here are some links that will help you.

https://www.gardeningknowhow.com/ornamental/trees/palms-trees/palm-tree-planting-outdoors.htm
https://en.wikipedia.org/wiki/Ravenea
https://en.wikipedia.org/wiki/Phoenix_(plant)

This article will help you with care requirements.
https://www.gardeningknowhow.com/houseplants/palms/growing-palms-indoors.htm

While most Palms don't have invasive roots, the root systems extend laterally as far as the crown of leaves.
Choose a smaller specimen for areas of concern.
Plant your Palm where lateral root grown is not an issue.

Pygmy Date Palms are often planted around patios due to their smaller size therefore smaller root system.

This article will refresh you on the care requirements.

https://www.gardeningknowhow.com/edible/fruits/date/date-palm-tree-care.htm

It is always risky to mound up soil or mulch around a tree, especially as high as 20 inches. This can lead to root rot and infections on the trunk, and can end up suffocating the roots. Gravel is better than soil, but it will still restrict air flow to the roots somewhat, especially since it will be so deep.

There may be a way to do this without killing the trees by adding perforated pipes around them, in the gravel, to provide aeration.

Another possibility might be to "transplant" the palms- dig them up and plant them in the same location after the soil level is raised- as described in this article:
http://edis.ifas.ufl.edu/ep001

Palms tend to recover better than other mature trees after transplantation because of their specialized roots.

Please try again to upload the picture.